Minimizing differential modal gain in cladding-pumped EDFAs supporting four and six mode groups.

We employ a Genetic Algorithm for the purpose of minimization of the maximum differential modal gain (DMG) over all the supported signal modes (at the same wavelength) of cladding-pumped four-mode and six-mode-group EDFAs. The optimal EDFA designs found through the algorithm provide less than 1 dB DMG across the C-band (1530-1565 nm) whilst achieving more than 20 dB gain per mode. We then analyze the sensitivity of the DMG to small variations from the optimal value of the erbium doping concentration and the structural parameters, and estimate the fabrication tolerance for reliable amplifier performance.

High-energy, in-band pumped erbium doped fiber amplifiers.

We have demonstrated and compared high-energy, in-band pumped erbium doped fiber amplifiers operating at 1562.5 nm under both a core pumping scheme (CRS) and a cladding pumping scheme (CLS). The CRS/CLS sources generated smooth, single-peak pulses with maximum pulse energies of ~1.

Accurate modal gain control in a multimode erbium doped fiber amplifier incorporating ring doping and a simple LP₀₁ pump configuration.

We experimentally validate a numerical model to study multimode erbium-doped fiber amplifiers (MM-EDFAs). Using this model, we demonstrate the improved performance achievable in a step index MM-EDFA incorporating a localized erbium doped ring and its potential for Space Division Multiplexed (SDM) transmission. Using a pure LP₀₁ pump beam, which greatly simplifies amplifier construction, accurate modal gain control can be achieved by carefully tuning the thickness of the ring-doped layer in the active fiber and the pump power.

Optimizing the pumping configuration for the power scaling of in-band pumped erbium doped fiber amplifiers.

A highly efficient (~80%), high power (18.45 W) in-band, core pumped erbium/ytterbium co-doped fiber laser is demonstrated. To the best of our knowledge, this is the highest reported efficiency from an in-band pumped 1.